[linux-dvb] FusionHDTV Dual Digital zl10353 / dee1601 tuning

Gerald Hofer hofer at sgi.com
Tue Sep 12 02:14:25 CEST 2006


> Is there something different between the PCI and the USB parts? One
> seems to tune to SBS (well mostly) and the other doesn't. I'm lost....

I installed a DVICO dual digital over the weekend and came across a few
problems as well. But it is now working for me perfectly.

First I describe the setup that I got to work:

I am using OpenSuSE 10.1, kernel 2.6.16.21-0.13-default in an old i386
P3. The hg tree I installed according to
http://www.linuxtv.org/wiki/index.php/How_to_install_DVB
was from 9/9/06 :
hg clone http://linuxtv.org/hg/v4l-dvb
It compiled and installed without problems. I tested Chris's test tree
as well and it gave some errors - so I did not bother).

The scan file for Brisbane does need the +166667Hz offset. This is my
scan file:

# cat /usr/share/dvb/scan/dvb-t/au-Brisbane
# Australia / Brisbane (Mt Coot-tha transmitters)
# T freq bw fec_hi fec_lo mod transmission-mode guard-interval hierarchy
# ABC
T 226500000 7MHz 3/4 NONE QAM64 8k 1/16 NONE
# Seven
T 177500000 7MHz 2/3 NONE QAM64 8k 1/8 NONE
# Nine
T 191791667 7MHz 3/4 NONE QAM64 8k 1/16 NONE
# Ten
T 219500000 7MHz 3/4 NONE QAM64 8k 1/16 NONE
# SBS
T 585791667 7MHz 2/3 NONE QAM64 8k 1/8 NONE

I actually used most of the time kaffeine for testing as it gives me a
instant look at the picture and I can see visual artefacts direct. So I
made these changes also to ~/.kde/share/apps/kaffeine/dvb-t/au-Brisbane

I then generated a channels.conf file:
dvbscan -a /dev/dvb/adapter2 /usr/share/dvb/scan/dvb-t/au-Brisbane >
~/.tzap/channels.conf

I then edited this file and only included the channels I want (no HD at
the moment...) and used it in mythtv instead of a scan to define the
channels:
ABC TV
Brisbane:226500000:INVERSION_AUTO:BANDWIDTH_7_MHZ:FEC_3_4:FEC_3_4:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:512:650:577
ABC2:226500000:INVERSION_AUTO:BANDWIDTH_7_MHZ:FEC_3_4:FEC_3_4:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:2307:2308:578
7
Digital:177500000:INVERSION_AUTO:BANDWIDTH_7_MHZ:FEC_2_3:FEC_2_3:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:1025:1026:1344
Nine
Digital:191791667:INVERSION_AUTO:BANDWIDTH_7_MHZ:FEC_3_4:FEC_AUTO:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:513:660:1025
TEN
Digital:219500000:INVERSION_AUTO:BANDWIDTH_7_MHZ:FEC_3_4:FEC_1_2:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:512:650:1601
SBS DIGITAL
1:585791667:INVERSION_AUTO:BANDWIDTH_7_MHZ:FEC_2_3:FEC_AUTO:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:161:81:817
SBS DIGITAL
2:585791667:INVERSION_AUTO:BANDWIDTH_7_MHZ:FEC_2_3:FEC_AUTO:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:162:83:818

So this is the setup if everything works ;-)

The workaround to add the offset is annoying (especially if you have
other hardware at the same time that does not need this offset). But it
works for me...

But along the way I had a few problems:

I was running a Mythtv setup with a single external USB tuner DVICO
FusionHDTV DVB-T (MT352+Thomson7579) (0fe9:db11) on a Laptop for a while
 and everything worked as expected (with the original v4l-dvb that comes
with SuSE 10.1). Then I started the installation of the Dual digital in
a PC and nothing worked. SBS and Nine did not scan most of the time
(sometimes Nine worked) and most other programs had a lot of visible
errors and dropouts. I started to think about antenna problems (we are
40km south of MtCootha and don't have completely direct line of sight).
I then connected the antenna direct to the external USB tuner and got a
perfect picture on the Laptop. The same external USB tuner (and without
changing anything on the antenna connection) had visible dropouts and
locking problems when I connected it to the PC. So I figured that my
antenna signal was marginal and the PC introduced enough noise (probably
through the power supply) to push the signal over the digital edge.

I then added a masthead amplifier and a splitter and suddenly everything
started to work. I used a GME Kingray MHW34G (a F or FS would be
probably better, but his is what I found in a nearby shop on short
notice [it actually came packaged from Clipsal as 3105 MH34W)]- be sure
to get the wideband version - VHF and UHF. There is also a 24 db version
that might be enough). I have now a SNR above 90% on all channels (most
of them are 98%). And then it was easy to figure out that I needed the
+166667Hz offset for Nine and SBS.

The tuning problems Damien describe look very similar to what I saw when
I had a low signal - there was also a difference how the USB and the PCI
tuner worked and it was never repeatable. The reason why SBS behaves so
different from the others might be because SBS is the only channel in
Brisbane that is on UHV. Everything else is on VHF. So your antenna
setup could make a difference.

If you have other devices somewhere connected to the antenna -
disconnect them and see if it makes a difference.

I have also seen that the PC hardware (power supply?) can make a
difference. Now with a boosted signal that is strong enough the problem
is not visible and the reception is perfect on the PC as well - but that
might be also a source of a problem.

For the antenna problem I found the DTV forum very helpful.
http://www.dtvforum.info/
Go to the "Geographical Viewers Forum" and select your region. For
Brisbane that would be
DTV Forum Australia > Geographical Viewers Forums > Queensland >
Brisbane Viewers Forum
and select the "Get the best reception" topic.
It is obviously best to get a good antenna installer. They have testing
equipment that can give you BER and they can then tune the antenna setup
to reduce the BER and get the right signal strenght on each outlet (if
they can't give you a BER rate then look for a different installer...).
I was really only guessing and wanted a fix fast. I was lucky and it
made a huge difference (but I have not seen it in heavy rain yet :-)


The only remaining problem in my setup is the IR receiver on the
external USB box [DVICO FusionHDTV DVB-T (MT352+Thomson7579)
(0fe9:db11)]. The IR receiver in the Dual digital works fine.
With the latest hg tree it actually generates the input device and lircd
seems happy enough, but I can't get any output on irw. Has anyone made
this work?

Gerald





























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